1. Field of the Invention
This invention relates to computer user interface displays and, in particular, the use of a user interface separate from the standard user interface display.
2. Description of the Prior Art
There was a time when the most popular operating system for personal computers (DOS) did not include a graphical user interface. Any company could create a xe2x80x9cmenuxe2x80x9d or xe2x80x9cshellxe2x80x9d which would be the first program launched upon starting the computer and which would present options to the user for launching and managing various applications. Although graphics programming was difficult in the DOS environment, some companies even created graphical user interfaces that could then launch other programs.
Microsoft Corporation of Redmond, Wash., introduced such a graphical user interface for launching applications which it called xe2x80x9cWindowsxe2x80x9d. The first three versions of Windows were merely applications which ran under DOS and could be one of numerous items to be selected from a previously running shell or menu which might be offered by a company other than Microsoft. This continued to allow other companies to offer primary user interface programs to users without the user going through a Microsoft controlled user interface.
However, with the introduction by Microsoft of Windows 95(trademark), the initial loading of the operating system presents a Microsoft-developed graphical user interface at the outset, which occupies the entire screen display. As with its previous operating system products, Microsoft arranged with manufacturers of the standard computer hardware to include this operating system with each computer sold. With Microsoft""s domination of this market, it became impossible for other software vendors to present an interface to users other than as a Microsoft style icon within the Microsoft xe2x80x9cdesktopxe2x80x9d consisting of the entire screen display. This prompted a need for access to a user interface which could be presented outside of the standard computer screen display and therefore independent of the dictates of Microsoft for items within its xe2x80x9cdesktopxe2x80x9d.
Standard personal computers use VGA or Super VGA or XGA video display systems. These display systems operate in standardized graphics modes such as 640xc3x97480 pixels, 800xc3x97600 pixels, 1024xc3x97768 pixels, and 1280xc3x971024 pixels. When one of these display modes is selected, this is the entire area available for display. In the Microsoft Windows environment, the user instructs the Windows operating system to select one of these standard display modes and the Windows operating system then presents all of the applications and their icons within the selected display area. There is no way at present to cause the Windows xe2x80x9cdesktopxe2x80x9d to use less than the entire display area and still function as intended and allow another program from another vendor to control the remainder. What is needed is the ability to move obstructing video memory out of the way, and to make sure that nothing else that would be obstructing can subsequently be allocated into that space
The invention is a technique provided for adding and using a new user interface added to the standard user graphical display interface, for example in the border beyond the standard screen display area. Conventional video systems, such as VGA, SVGA and XGA video systems, include a defined border surrounding the display area. The original purpose of this border was to allow adequate time for the horizontal and vertical retrace of the electron gun in a cathode ray tube display. However, with the advent of LCD displays and as retrace speeds have increased in modern monitors, it is now possible to present a user interface display in this border. The border which can be controlled as a user interface is a portion of what is known as the xe2x80x9coverscanxe2x80x9d. This invention is a method for presenting one or more additional or secondary user interfaces, for example, in the overscan area surrounding the conventional user interface display often called the desktop.
When the electron gun in a CRT retraces to the left of the screen or the top of the screen, it requires a significant amount of time relative to the presentation of a scanned line of data. During the retrace, the electron gun is turned off (xe2x80x9cblankedxe2x80x9d). If the blanking time required for the retrace is equal to the amount of time available, there is no usable overscan. However, modern monitors have become much faster in their retrace speeds, leaving a significant amount of time when the electron gun need not be blanked, allowing a displayable border. In the prior art, although the border is usually xe2x80x9cblackxe2x80x9d (the gun is turned off), it is well known to specify that the border shall be given any one of six colors. Standard BIOS allows a specification of this color. The desired color is simply specified in one of the registers for the video controller. No data for this color is stored in the buffer of video memory for the display. This invention establishes an additional video buffer for the border and allows this buffer to be written with display data like the regular display buffer. The display area is thereby expanded, on one or more edges, to provide a visible area previously invisible. The pixels within this newly visible area of the display are made accessible to programs through an application programming interface (API) component of this invention. A program incorporating a graphical user interface may be displayed in the previously blanked area of the display, functionally increasing the accessible area of the display without hardware modification.
The invention is a method for displaying an image on a video display system in an area outside of the primary display area generated by the video display system. Two dimensions define the standard display area, each specifying a number of pixels. Selecting a video xe2x80x9cmodexe2x80x9d specifies these dimensions. The method is accomplished by adjusting parameters for the video display system to increase the number of pixels in at least one dimension of the display system. The number of pixels which is added is less than or equal to the difference between the number of pixels specified in the video mode and a maximum number of pixels which the video display system can effectively display. This difference is the overscan area. Because all interface displays are created by writing a desired image to a buffer or memory for the video display, the method requires allocating additional video display memory for the increased pixels. The image written to such memory is then displayed by the system alongside the original display area.
In a first embodiment, only the vertical dimension is increased and the overscan user interface is presented above or below the primary display area. Alternatively, the horizontal dimension may be increased and the overscan user interface displayed to the right or the left of the primary display area. Similarly, the interface image may be displayed on any or all of the four sides of the primary display area.